An imaging device represented by a camera is widely used for photographing for appreciating photography, an industrial measurement/object recognition system, risk detection for vehicle, a crime-prevention monitoring system, and the like. In those use forms, it is often necessary to obtain not only an image of a photographic subject but also spatial information such as a distance, a visual field direction, and the like.
As a technique which makes it possible to obtain the spatial information, by use of an image sensor and a coded-aperture pattern, a technique is known in which information on a space and an incidence angle of a luminous flux incident to the image sensor is obtained by performing decoding processing based on Fourier transform (for example, see Japanese Patent Application Publication No. 2008-191661).
Additionally, by using a reconstructible or active spatial light modulation element as the coded-aperture pattern, a technique is known in which an image quality is improved from an image imaged by a plurality of types of coded-aperture patterns by performing decoding processing (for example, see Japanese Patent Application Publication No. 2008-542863).
Furthermore, as an element used as such a spatial light modulation element, a liquid crystal element, or alternate technique, or the like has been proposed (for example, see Japanese Patent Application Publication Numbers 2005-316321, 2005-316316, and Beni, G. and Hackwood, S., ‘Appl. Phys. Lett. Vol. 38, Issue 4’, 207-209, USA, 1981).